Making your own bong head isn't hard, but most people screw it up on the first attempt because they skip the math.
A bong head is the top assembly where your bowl sits, the percolation happens, and smoke gets pulled into the chamber below. When you buy a pre-made piece, it's done for you. When you make your own, you're working with glass tubing, drill bits, and a whole lot of patience. I've been doing this since the mid-2000s. I've broken more glass than I care to count. Start with 18mm or 14mm male joint tubing, whichever matches your existing rig. The length you want depends on how tall your water chamber is and how much draw resistance you're comfortable with. Most people make theirs around 60 to 80 millimeters tall. Anything shorter and the water seal is unpredictable. Anything taller and you're dealing with excessive drag unless you add serious percolation. The actual assembly goes like this. You take the tubing and drill holes near the bottom for water percolation. Then you cap the top end with a bowl insert or a separate tenon if you want to use a standalone piece. The holes you drill determine how much smoke actually bubbles through the water before hitting the downstem area. More holes means more filtration but also more pull resistance. There is a balance point and you find it by testing, not by guessing.
I've seen people try to use standard masonry bits on borosilicate and wonder why the glass cracks within twenty seconds. You need a carbide or diamond-tipped bit made for glass. Start at low speed, apply steady but light pressure, and use water as a coolant. Dripping water from a squeeze bottle directly onto the bit works fine. Let the bit do the cutting. If you force it, the glass shatters and you've wasted an hour. Here is the part nobody mentions. The thickness of the glass matters more than you think. Standard tubing is about 3 millimeters thick. That is fine for basic rigs. But if you are drilling multiple holes close together, the structural integrity drops fast. I once drilled a dozen 4mm holes in a tight cluster on a 50mm piece and it cracked during the first heat cycle, right at the hole nearest the rim. My workaround was simple: space the holes at least 8mm apart and keep the diameter under 5mm unless you are using thick-walled tubing. That gave me enough filtration without weakening the joint. For the top cap, you have options. A simple flat piece of glass fused on with a recessed bowl pocket works if you're comfortable with a torch. Most people who try this for the first time end up with an uneven surface that makes packing impossible. A much easier route is buying an 18mm female tenon and a separate perc module and building around those. It costs more upfront but saves you from re-doing the whole thing three times.
The percolation pattern inside the head also changes how the piece performs. A shower head style with multiple small holes spread across the lower section gives smoother hits than one big hole. I measured this myself with a simple airflow test. Three 3mm holes produced about the same draw resistance as one 5mm hole but moved significantly more water. That difference translates directly to filtration quality. There are things this approach won't fix. If your base rig already has poor water volume or a narrow downstem, a DIY head won't compensate for that. The head is one variable in a system. You can't out-build a bad design. Also, hand-drilled holes are never perfectly round. They don't need to be. Smoke doesn't care about geometry the way you'd think. But rough edges on the inside of the hole collect resin faster than smooth ones, and that buildup changes your draw over time. If you want a downloadable reference for hole spacing and dimensions, I keep a simple PDF on my site with the measurements I use for 14mm and 18mm builds. It covers hole placement patterns, spacing minimums, and the torque limits for threading tenons into glass. Search for the PDF and you will find it.
Get the Full Details
The real takeaway here is that DIY bong heads are about iteration. Your first one probably won't be great. That is normal. The second one will be better. By the fourth build you'll know exactly what your preferences are and you'll stop overthinking the variables. Just don't skip the cooling water when you drill. It is the single most common reason people quit after one attempt.
